From the graph:

The Boston public library has 14.6 millions of volumes.

The Harvard University has 14.7 millions of volumes.

Let n represent the number of more volumes the Harvard University had than

the Boston public library.

Write the verbal expression to represent the situation:

Rewrite the equation:

According to subtraction property of equality: Subtract 14.6 from each side.

     (Apply commutative property of addition: )

                      (Apply additive inverse property: 1)

                            (Apply additive identity property: )

                                          (Subtract: )

The Harvard University has 0.1 more millions of volumes than Boston Public library.